This paper describes basic researches on learning contexts of “water” in chemical education. First, the features of “water” as teaching materials were discussed. Second, some previous efforts for the context-based learning of “water” in foreign and domestic cases were summarized. And third, two examples for the learning contexts of “water” were proposed on the basis of some lesson practices.本研究の一部は，平成25～27年度科学研究費補助金基盤研究C（課題番号：25350203，研究代表者：網本貴一）および平成25～28年度科学研究費補助金基盤研究A（課題番号：25242015，研究代表者：古賀信吉）の助成を受けて行ったものである。